Remotely Triggered Earthquakes

We just learned about the Megathrust Earthquake, the earth's most powerful type of quake.

Another type of earthquake is the Remotely Triggered Earthquake.

Sometimes when one earthquake is large enough, it's mainshock or aftershock can cause other earthquakes.
But sometimes a bunch of earthquakes happen in one area within a few days or weeks of each other, but too far to be affected by the other earthquake's mainshock or aftershock.
This can be confusing, because if a bunch of earthquakes are happening in the same state, scientists want to know what is causing them all.

When a bunch of earthquakes happen close by but not close enough for aftershocks to cause it, these are the Remotely Triggered Earthquakes.
Many scientists think these are caused by things like magma or water flows underground, moving around and shifting the tectonic plates and causing the faults to become active and cause quakes.


(from: wikipedia - remotely triggered earthquakes)


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Megathrust Earthquake

We just learned about the Intraplate Earthquake that happens inside a tectonic plate.

Another type of earthquake is a Megathrust Earthquake.

This is when one of the tectonic plates slides under another plate, which we learned is a Dip-Slip Fault

These are the most powerful earthquakes on the planet, and can cause a lot of destruction.


(from: wikipedia - megathrust earthquake)


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Intraplate Earthquake

We just learned about the Interplate Earthquake where two plates bump into each other and cause an earthquake.

Another type of earthquake is an Intraplate Earthquake.

This is when an earthquake happens in the middle of a tectonic plate, not near the edges.
Because this isn't by a fault line or border of the plate, scientists are not really sure why these happen, and they do a lot of research to see if there is a hidden fault line somewhere they did not know about.


(from: wikipedia - intraplate earthquake)


Kid Facts - Blast from the past: Sponge Iron

Interplate Earthquake

We just learned about the Doublet Earthquake.

Another type of earthquake is the Interplate Earthquake.

This is an earthquake that happens where two tectonic plates meet.
These are the types of earthquakes that happen more than any other.


(from: wikipedia - chuetsu earthquake)


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Doublet Earthquake

We just learned about the Blind Thrust.

Another type of earthquake is the Doublet Earthquake.

We learned before that most earthquakes have a big mainshock, with a smaller beginning called a foreshock, and a smaller quake after called the aftershock.

Sometimes two big earthquakes happen at the same time very near each other.
When this happens, it's like a double quake, just like the name doublet earthquake.
So when this happens there are two foreshocks, two mainshocks and two aftershocks.
It can be very hard for seismologists to figure out which quakes came from which fault.


(from: wikipedia - doublet earthquake)


Kid Facts - Blast from the past: Iron Ore

Blind Thrust

We just learned about the Thrust Fault where the earth slips in the reverse direction.

One type of earthquake is a Blind Thrust earthquake.

Usually earthquakes happen in places where there are faults that have been mapped out, so people know where they are and know what to expect.

Sometimes earthquakes happen in areas where people did not think there were any faults, so it is like a blind earthquake because no one was expecting it, and no one was looking there for an earthquake.


(from: wikipedia - blind thrust earthquake)


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Thrust Fault

We just learned about the Aftershock that happens after the biggest part of the earthquake.

We've learned about the Dip Slip fault before.

Another fault type is a Thrust Fault.
This is a lot like the dip-slip, but the slip goes in the opposite direction.
Sometimes they even call it a reverse thrust fault.


(from: wikipedia - thrust fault)


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Aftershock

We just learned about the Foreshock and Mainshock of an earthquake.

After the Mainshock comes the Aftershock.

When the earthquake passes it's strongest part of the mainshock, any of the other quakes or ground shaking is part of the aftershock.

Separating the earthquake into the three parts (Foreshock, Mainshock and Aftershock) helps earthquake scientists study each part of the quake, and learn about why the earth acts the way it does.


(from: wikipedia - earthquake)


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Mainshock

We just learned about the Foreshock that happens before the biggest part of the earthquake.

The biggest part of the earthquake is called the Mainshock.
This is when the earthquake is at it's strongest force.


(from: wikipedia - earthquake)


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Foreshock

We just learned about the Ring Fault.

Another part of earthquake science is the Foreshock.

Most earthquakes have multiple shocks, where the earth is shaking.
The first one that is smaller before the biggest one is called the foreshock.


(from: wikipedia - earthquake)


Kid Facts - Blast from the past: Upsetting

Ring Fault

We just learned about the Listric Fault.

Another type of fault is a Ring Fault.

This fault is in a crater or a volcano, where the volcano has collapsed, or the ground caved in after getting hit by a meteorite.


(from: wikipedia - chesapeake bay impact crater)


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Listric Fault

We just learned about the Oblique-Slip Fault.

Another earthquake fault is a Listric Fault.

This is like the Dip-Slip fault that we learned about before, but the fault line makes a curved line where the earth's crust slides down.

(from: wikipedia - fault (geology))


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Oblique-Slip Fault

We just learned about the Dip-Slip Fault.

Another type of earthquake fault is the Oblique-Slip Fault.

This is when two the tectonic plates move, and the earth's crust bumps into each other in both a Strike-Slip and Dip-Slip way.

That means the earth went side to side, and up and down.


(from: wikipedia - fault (geology))


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Dip-slip Fault

We just learned about the Strike-slip fault.

Another type of earthquake fault is the Dip-slip fault.

This happens when the tectonic plates hit each other, and one of them slips down and the other slips up.


(from: wikipedia - fault (geology))



(from: wikipedia - fault (geology))


Kid Facts - Blast from the past: Fuller

Strike-Slip Fault

We just learned that a fault is when two tectonic plates crash into each other.

There are different types of faults, and different ways that the earth's crust moves during faults.
One type of fault is a Strike-slip fault, also known as a wrench fault, tear fault or transcurrent fault.

When an earthquake happens at one of these faults, the ground shifts side to side.
To show this, put your two hands in front of you on a table, with your palms flat on the table.
Have your hands touching at the sides of your thumbs and pointer fingers.
Slide your right hand forward away from you, and slide your left hand toward your body.
That is the same way the earth moves, slipping the two pieces of the earth's crust next to each other, but keeping them touching.

(from: wikipedia - fault (geology))


(from: wikipedia - fault (geology))


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Fault

We just learned about the Tectonic Plates.

Another part of earthquake science is a fault.

When the tectonic plates smash into each other, the place where the earth's crust touches from two different plates is called a fault.
When the plates move, not every part of the crust will run into other parts.
There are a bunch of different types of faults, depending on how the two pieces of crust run into each other.


(from: wikipedia - earthquake)


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Tectonic Plates

We just learned about the earthquake Hypocenter.

Another part of earthquakes is the Tectonic Plates.

The scientist who study earthquakes have mapped out 15 big areas on the earth, on every continent and around the oceans.
These areas are called tectonic plates, and they move around little by little every year.
When one tectonic plate area moves, it bumps into another tectonic plate, and it causes an earthquake!

These plates are millions of miles wide, and over 60 miles deep.
Because they are so huge, when they bump into each other the earth crashing together has a lot of force and makes a big problem.


(from: wikipedia - list of tectonic plates)


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Hypocenter

We just learned about the earthquake Epicenter.

Another important thing in earthquake science is the Hypocenter.

This is the spot underground where the earthquake first started.
The epicenter is right above the hypocenter, but at the surface of the earth.


(from: wikipedia - hypocenter)


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Epicenter

Let's keep learning about Earthquakes.

When an earthquake happens underground, the spot on the earth's surface above where the earthquake is strongest is called the epicenter.


(from: wikipedia - epicenter)


Kid Facts - Blast from the past: Cross Peen Hammer

Earthquakes

We've learned a whole lot about how to work with metal.
Everything from furnaces to get the metal from iron ore, to working with it on anvils, to using it on machines like lathes or mills.

Let's start learning a little bit about Earthquakes.
Earthquakes happen all over the world, even underwater!
There are scientific tools for predicting and measuring quakes, and there is a lot of scientific study over what makes an earthquake happen.

A scientist who studies earthquakes is called a seismologist.


(from: wikipedia - earthquake)


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